Stabilized lubricating oil



Patented June 7, 1938 PATENT OFFICE STABILIZED LUBBIOATING on.

Waldo L. Steiner, Ponca City, Okla, assignor to- Continental Oil Comp y,Ponca Oity,.0kla., a corporation of Delaware I No Drawing.

-., 12 Claims.

cause cloudiness, precipitation or other objectionable characteristicsin the finished lubricant. The change may be 'due to the properties ofthe addition material, the properties of the oil, or a I combination ofthe two. In some cases. the change is evidenced immediately on blending;in

others considerable time may be required before the objectionable changeis apparent. Generally, the cloudiness or precipitate disappears or goesback into homogeneous solution with the hydrocarbon oil when thelubricant is put into actual service. This reversal of action. is nodoubt due in part to the influences of temperature, pressure and metalcontact experienced in actual lubricating service. e

Cloudy oils are diflicult to market and may be the source ofconsiderable sales resistance. In fact, it may be the direct cause ofmarketing fail-- are of 'a product which should be a market success. Thecloudiness or. slight precipitate, as a rule, does not impair thelubricating qualities of the lubricant.

I have found that cloudiness usually results from the presence of freeorganic acids or substances which will react acid in the lubricant.

86 The degree of cloudiness i's'greatly influenced by the presence ofother substances in the lubricant such as sulphur, soaps and the like.

The primary object of my invention is to stabilize lubricants andprevent the formation of 40 a cloud or precipitate.

' Another object of my invention is to accomplish this result cheaplyand without in any way impairing the desirable lubricating qualities ofthe lubricant.

Other objects will be apparent to those skilled in the art on readingthe following description of my invention.

In general, my invention comprises the addi- 50 tion of organicsubstances which are basic or alkaline with respect to the hydrocarbonlubricants which have a tendency 'to cloud or give a precipi tate due totheir free acid content or content of acidic substances. 55 Thefollowing example is given to clarify my 'thenic acidis very difllcult.

Application January 20, 1933, Serial No. 652,698

invention but is not to be considered as a limitation to my invention.

A high fllm strength free wheeling gear lubricant can be made by theaddition of a sulphur base oil and lead naphthenate to a hydrocarbon 5mineral oil. The percentage of these constituents in the finishedlubricant can be varied over wide limits depending upon a numberofli'actors and particularly on the degree of high fllm strength desiredin the finished lubricant. A common 1 characteristic of all of theseblends is that on standing (1 to 30 days) a substance insoluble. in thehydrocarbon oil separates, and, if not disturbed, will slowly settle tothe bottom of the container. The insoluble material which sepa- 15 ratesis visible and detracts from the sales value of the lubricant. This isparticularly true of the bottom portion of the container wheretheprecipitate has concentrated. To my knowledge this precipitate does notimpair the lubricating qu'ali- 20 ties of the oil.

In my study of the insoluble material, I found that it was influencedand dependent on the free acid content of the lubricant. I could greatlyinhibit the formation of the insoluble substance by 25 carefully freeingthe lead n'aphthenate oi allfree naphthenic acids. This is notcommercially feasible, since freeing the lead naphthenate ofnaphnaphthenate will release free acid again until a 30 certainequilibrium between lead naphthenate acid is reached.

The addition of organic bases to theblend tends to neutralize the 'freenaphthenic acid and substantially prevents formation of insolublematerial. At any rate, the formation of the insoluble substance isinhibited to a point where it is. not a cause of sales resistance. g

In practicing my' invention 1 determine by titration the approximate orexact'amount crime 40 acid present in the lubricant and sumcientorganicbase is added to neutralize the determined amount of free acid-withabout 5 to excess of the base. The acid content of the. various 7constituents of the finished lubricant may be de- 45 termined in theusual manner'and the organic base added to the acidic constituents orblended with the. acidic constituents and the mineral oil in one step.

The organic base should be thoroughly incor- 5o porated in thelubricant. With viscous lubricants the blending should be done at hightemperatures, say up to 200 F. or above, the temperature used dependingon the consistency of the mixture and upon the organic base being used.A

Furthermore, lead all :1 Organic bases as used in the description of myinvention may include such substances as the nitrogen containing organiccompounds. Tri: ethanolamine has been found to be entirely satisfactoryand better than many of the other organic bases. Diphenylamine may beused. Analine is not sufliciently basic to be of much value. Nearly allof the secondary and tertiary amines are satisfactory. ;Some of thesubstituted pri mary amines maybeused with success.

Since the amount of free acid occurring in th lubricant is usuallysmall, the amount of organic base used is, as a rule, a very smallpercentage based on the lubricant volume.

ness in the general sense to indicate both the appearance of a cloud inthe lubricant and the formation of the precipitate.

The sulphur base is prepared from a fatty oil and sulphur. F'atty oilsas obtained commercially are not absolutely free of acid and theadditionof sulphur tends to saponify part of the fatty oils to formfatty acid; so that considerable free fatty acid is usuallyfound in thesulphur base. It may be that a combination of the free fatty acid andthe sulphur base with the free fatty acid from the lead'naphthenate maycause the difllculty. At any rate when an organic base is addedaccording to my invention, the difliculty is obviated.

Having .thus described my invention, what I claim is:

1. A lubricant comprising in combination a hydrocarbon oil, an additionproduct of acidic nature and a small quantity of an organic base.

2. A lubricant comprising in combination a hydrocarbon oil, an additionproduct of acidic nature and a, small quantity of an organic basecontaining an amino group,

3. A lubricant comprising in combination a hydrocarbon oil, an additionproduct which will re-,

lease an acid and a small quantity of an organic base.

4. A lubricant comprising in combination a hydrocarbon oil, an acidreleasing addition product and a secondary amine.

5. A lubricant comprising in combination a hydrocarbon oil, an acidreleasing additionproduct and a tertiary amine.

6. A lubricant comprising in combination a hydrocarbon oil, an acidreleasing addition product and a substituted primary amine.

7. A lubricant comprising in combination a hy-. drocarbon oil, an acidreleasing addition product and a diphenylamine. 8. A lubricantcomprising in combination a hydrocarbon oil, an acid releasing additionproduct 1 and a triethanolamine.

9. A lubricant comprising in combination ahydrocarbon oil, leadnaphthenate and an organic base.

10. A lubricant comprising in combination a hydrocarbon oil, leadnaphthenate and triethanolamine- 11. A non-clouding lubricafitcomprising a hydrocarbon oil, lead naphthenate and a small quantity ofamine.

12. A non-clouding lubricant comprising in combination a hydrocarbonoil, lead naphthenate and a small quantity of diphenylamine.

WALDO L. STEINER.

